Final answer:
Arteries carry oxygenated blood away from the heart, veins carry deoxygenated blood back to the heart, and capillaries allow for the exchange of substances between the blood and tissues.
Step-by-step explanation:
Blood vessels are the tubes that carry blood throughout the body. The three major types of blood vessels are arteries, veins, and capillaries.
Arteries carry oxygenated blood away from the heart to the body tissues. They have thick muscular walls to withstand the pressure of blood being pumped by the heart. The largest artery in the body is the aorta.
Veins carry deoxygenated blood back to the heart. They have thinner walls than arteries and often have valves to prevent backflow of blood. The two largest veins in the body are the superior vena cava and the inferior vena cava.
Capillaries are tiny, thin-walled blood vessels that connect arteries and veins. They allow for the exchange of oxygen, nutrients, and waste products between the blood and the surrounding tissues.